Glossary of common biostatistical and epidemiological terms
- Peter A L Bonis, MD
Peter A L Bonis, MD
- Chief Medical Officer of Clinical Effectiveness (UpToDate, Clinical Drug Information, and Emmi Solutions)
- Deputy Editor — Gastroenterology/Hepatology
- Adjunct Professor of Medicine
- Tufts University School of Medicine
- Section Editors
- Joann G Elmore, MD, MPH
Joann G Elmore, MD, MPH
- Editor-in-Chief — Primary Care (Adult)
- Section Editor — General Medicine
- Professor of Medicine, David Geffen School of Medicine at UCLA
- David M Rind, MD
David M Rind, MD
- Section Editor — General Medicine
- Chief Medical Officer
- Institute for Clinical and Economic Review
- Assistant Professor of Medicine, Part-time
- Harvard Medical School
This topic review will provide a catalog of common biostatistical and epidemiological terms encountered in the medical literature.
STATISTICS THAT DESCRIBE HOW DATA ARE DISTRIBUTED
Measures of central tendency — Three measures of central tendency are most frequently used to describe data:
●Mean equals the sum of observations divided by the number of observations.
●Median equals the observation in the middle when all observations are ordered from smallest to largest; when there are an even number of observations the median is defined as the mean of the middle two data points.
●Mode equals the observation that occurs most frequently.To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
- Moriarty PM. Relative risk reduction versus number needed to treat as measures of lipid-lowering trial results. Am J Cardiol 1998; 82:505.
- Lubsen J, Hoes A, Grobbee D. Implications of trial results: the potentially misleading notions of number needed to treat and average duration of life gained. Lancet 2000; 356:1757.
- de Craen AJ, Vickers AJ, Tijssen JG, Kleijnen J. Number-needed-to-treat and placebo-controlled trials. Lancet 1998; 351:310.
- Weissler AM. A perspective on standardizing the predictive power of noninvasive cardiovascular tests by likelihood ratio computation: 1. Mathematical principles. Mayo Clin Proc 1999; 74:1061.
- Leening MJ, Vedder MM, Witteman JC, et al. Net reclassification improvement: computation, interpretation, and controversies: a literature review and clinician's guide. Ann Intern Med 2014; 160:122.
- Pencina MJ, D'Agostino RB Sr, Demler OV. Novel metrics for evaluating improvement in discrimination: net reclassification and integrated discrimination improvement for normal variables and nested models. Stat Med 2012; 31:101.
- Porta N, Bonet C, Cobo E. Discordance between reported intention-to-treat and per protocol analyses. J Clin Epidemiol 2007; 60:663.
- Gravel J, Opatrny L, Shapiro S. The intention-to-treat approach in randomized controlled trials: are authors saying what they do and doing what they say? Clin Trials 2007; 4:350.
- STATISTICS THAT DESCRIBE HOW DATA ARE DISTRIBUTED
- Measures of central tendency
- Measures of dispersion
- TERMS USED TO DESCRIBE THE FREQUENCY OF AN EVENT
- TERMS USED TO DESCRIBE THE MAGNITUDE OF AN EFFECT
- Relative risk
- Odds ratio
- Absolute risk
- Number needed to treat
- TERMS USED TO DESCRIBE THE QUALITY OF MEASUREMENTS
- MEASURES OF DIAGNOSTIC TEST PERFORMANCE
- Predictive values
- Likelihood ratio
- Net reclassification improvement and integrated discrimination improvement
- EXPRESSIONS USED WHEN MAKING INFERENCES ABOUT DATA
- Confidence interval
- Credible interval
- TERMS USED IN MULTIVARIATE ANALYSIS
- TIME-TO-EVENT ANALYSIS (SURVIVAL ANALYSIS)
- Kaplan-Meier analysis
- Cox proportional hazards analysis
- STUDY DESIGNS
- Cohort study
- Case-control study
- Randomized controlled trial
- - Intention to treat
- Mendelian randomization